Carotid endarterectomy and intraoperative emboli detection: Correlation of clinical, transcranial Doppler, and magnetic resonance findings

Carotid endarterectomy (CEA) performed with continuous transcranial Doppler (TCD) monitoring provides a unique opportunity to determine the number of cerebral microemboli and to relate their occurrence to the surgical technique. The purpose of this study, was to assess in CEA the impact of cerebral microembolism on clinical outcome and brain morphology. We also evaluated the influence of the audible TCD signal on the surgeon and his/her technique. In a prospective series of 301 endarterectomies, brain function was monitored with electroencephalography an TCD ultrasonography. Preoperative and intraoperative risk factors were Entered in a logistic regression analysis program to assess their correlation with cerebral outcome. To evaluate the impact of cerebral microembolism on brain morphology, we compared preoperative and postoperative magnetic resonance (MR) images of the brain in a subgroup of 40 patients. Microemboli (> 10) observed during the dissection phase of the operation were related to intraoperative (P < 0.002) and postoperative (P < 0.02) cerebral complications. Microemboli that occurred during shunting were also related to intraoperative complications (P < 0.007). Finally, the phenomenon of > 10 microemboli during dissection was significantly (P < 0.005) related to new hyperintensive lesions on the postoperative T-2-weighted MR images. The presence of microembolism (> 10) during the dissection phase of carotid endarterectomy shows a statistically, significant relationship with perioperative cerebral complications and with new ischemic lesions on MR images of the brain. Microembolism during shunting is also related to intraoperative complications. Surgeons can be guided by the audio Doppler and emboli signals by changing their technique, which may result in a decline of the intraoperative stroke rate.